Exemplary embodiments of the present disclosure relate to a retainer provided to stably fix turbine blades inserted into respective dovetail grooves of a turbine disk, and more particularly, to a gas turbine having a structure improved to facilitate inspection or repair of a plurality of turbine blades.
In general, an engine or an apparatus including a turbine, such as a gas turbine or a steam turbine, is called a turbo machine. The turbo machine is a power generator which converts thermal energy of fluid into rotational force, which is a type of mechanical energy. The turbo machine includes a rotor which is axially rotated by fluid, and a stator which supports and encloses the rotor.
The gas turbine may be a kind of internal combustion engine, including a turbine which converts thermal energy into mechanical energy by expanding high-temperature and high-pressure combustion gas generated by combusting a mixture of fuel with air compressed to a high pressure by a compressor. Each of the compressor and the turbine obtains rotational force from a rotor unit.
In order to form the rotor unit of the compressor or the turbine, the gas turbine includes a plurality of compressor rotor disks each of which includes a plurality of compressor blades arranged around an outer circumferential surface thereof. A tie bolt is provided to couple the rotor disks with each other and enable them to integrally rotate and to couple a plurality of turbine rotor disks with each other so that the turbine rotor disks each having an outer circumferential surface around which a plurality turbine blades are arranged can be integrally rotated. The tie bolt has a well-known configuration in which it extends through a central portion of the rotor disk of the compressor and a central portion of the rotor disk of the turbine and couples the rotor disk of the compressor with the rotor disk of the turbine.
Blades to be mounted to the rotor disk are primarily inserted into respective dovetail grooves and then fixed to front and rear portions of the dovetails by retainers. The conventional retainer functions to simply fix a blade in place, but must function as a cooling air seal for cooling blades disposed at positions corresponding to first to third stages. Furthermore, in the conventional gas turbine, when it is necessary to repair the blades, there is required a complex process including disassembling a plurality of casings enclosing the rotor, separating the blades from the dovetail grooves using separate equipment in a work site, and reassembling the parts. Furthermore, because it is not easy for a worker to remove the retainer from the blades, measures for solving this problem are required.